Investigations of Phytoplankton in the Varna Bay (2005-2014)

In this paper phytoplankton development is monitored in the region of Varna Bay (2005 - 2014), like a part of cascade system, classified as a "hot spot" in the ecology of the Bulgarian coast and covers: Provadiyska River, Beloslav Lake, Varna Lake and Varna Bay. The present article discusses the changes in the multiannual dynamics of phytoplankton communities, biodiversity, quantitative and qualitative parameters related to environmental factors. It is reported constant trend of reduction of phytoplankton quantitative parameters and improving of the environmental conditions in the pelagial zone.